Why won’t my riding lawn
mower’s battery last as long as my pickup battery?It seems that I replace the mower battery
every two years.

J.M.

Dear J.M.:

Vibration is the biggest of
several things that kill riding lawn mower batteries.Some of the other things
that kill them are
neglect, heat, and cheap charging systems.I’ll touch on all of these, but first, the
biggie--vibration.

If you compare your mower’s
engine mounting to your pickup’s engine mounting, you will notice that
the mower’s
engine is bolted down solid to the frame.On the other hand, the pickup’s engine has rubber
motor (and transmission)
mounts between the engine and the frame.The mower’s engine transmits all of it’s vibration
into the frame, and,
since the battery is also mounted to the frame, it gets vibrated real
good.The rubber
mounts for the pickup’s engine
help keep the vibrations from getting to the frame, and since the
battery is
mounted indirectly to the frame and not the engine, it doesn’t get much
vibration at all.Now,
J.M., you didn’t
say if your mower had a one-cylinder engine or a two-cylinder engine,
but in
either
case, fewer cylinders means more vibration.More cylinders, like the six or eight that you
probably
have in your pickup,
results insmoother
running and less
vibration.Sure the
mower manufacturers
could put in rubber motor mounts and multi-cylinder engines but that
would cost
more and the darn things already cost too much!Back to the vibrations.Nearly
all batteries have positive and negative “plates” in them, but the
“plates” are
not solid.They are
made of a porous
granular material--usually lead alloys--that are loosely pressed
together, and
then held together by a mesh screen.This allows the liquid electrolyte to soak in and
make more
electricity.The
vibration shakes the
material out of the mesh, and when it builds up in the bottom of the
battery and
contacts the positive and negative plates, it shorts them out.The battery is dead.At this point, J.M., you
might think that you
could flush out the battery, charge it, and get another season out of
it.DON’T
TRY IT!The liquid
electrolyte
solution in the battery
is sulfuric acid.It
will eat through
clothes, eyes, skin, fingernails and bone.Nuff said, don’t try it.

Tne second of the other problems is
neglect.As grass
and stuff collect on
top of the battery, the collect moisture.The “stuff” and moisture
will conduct a
little electricity between the two battery connections and will slowly
run the
battery down--especially while the mower sits unused during our month
or two of
winter.If a
battery sits in a discharged
or dead state long enough, it gets a coating on the plates (sulfates).Once that happens, it can
never really be
brought back to a full charge.It
dies.

The heat problem comes from
the heat of the engine running.All
to
often the battery is located too close to the engine due to the limited
space
in a mower. The heat evaporates some of the liquid electrolyte out of
the
battery.If you
don’t or can’t replace
the evaporated liquid with distilled or rain water, then the battery
will run
dry.It dies.

Lastly, the cheap charging
system.Most of
today’s mowers rely on a
magnet and a coil of wire that inside the flywheel to
make a small
generator
to charge the battery.This
setup does
not put out much electricity to charge the battery, but it does keep
putting it
out all of the time the engine is running.This can lead to one of two problems.If you have a small yard, then the small amount of
electricity does not
fully charge the battery, and it slowly dies.If you have a big yard, then you may wind up over
charging the battery,
and that causes the liquid electrolyte to boil out of the battery, and it dies.Sure the mower manufacturers could put in a better
charging system, but
that costs more.As
I said before, the
darn things already cost too much.

Is there anything you can do
to extend the life of the battery?Yes,
when you get done mowing, clean off the top of the battery.This can be as simple as
using a whisk broom to brush off the top, or it can be as complicated
as using a shop vac
to clean
it off.Also, once
in a while (say
monthly), check the liquid level in the battery--if you can.Some batteries are
actually sealed, and they
can not be checked.When
checking the
liquid level, follow the warnings on top of the battery, and look down
in the
holes.If you see
ridges, then that is
the top of the plates, and you need to add distilled or rain water.I don’t recommend using
well water, but it
would be better than running the battery dry.The last thing you could do is get a small battery
maintainer and hook
it up to the battery if the mower will be setting unused a month or
more.

Now, J.M., if you do all of the
things that I recommended, you may--just may--get the battery to last
three
mowing
seasons instead of two.